The present invention relates to the twisting of individual elements of material utilizing “reverse axial torsion” and “reverse axial twist”, for a tight binding of twisted elements in a multi-element assembly.
One need for twisted multi-element assemblies is in the area of twisted cables, including, but not limited to, insulated conductors. One example of conventional twisting of multiple insulated conductors includes planetary cabling equipment such as drum twisters with rotating payoffs or bowplexers. Planetary assembly methods do not impart axial twist and a conductor remains essentially “straight” without torsion forces acting to hold the assembly together. Another example of twisting of multiple insulated conductors includes non-planetary assembly methods. Typical equipment for a non-planetary assembly are rotating drum twisters with stationary payoffs and single or double twist bunchers with stationary payoffs. Non-planetary cabling imparts an axial twist along each conductor in the same direction as the assembly twist or helix direction. The imparting of axial twists along each conductor in the same direction, however, results in torsion imparted on the individual conductors that causes the assembly to open up. As a result, the multi-element twisted assembly does not stay together as desired. Specifically with respect to utility power cables, a “loose” multi-element assembly impedes the ability to push the multi-element assembly into a conduit.
Accordingly, there is a need for more tightly bound multi-element twisted assemblies including cable elements, as well as generally in other individual elements in a variety of other applications.